Top 500 supers: Big Blue Roadrunner outpaces Jaguar

Petaflops abound

SC08 The Supercomputing 2008 trade show kicked off this past weekend, and the centerpiece of the annual event, which is being hosted in Austin, Texas, is the Top 500 ranking of supercomputers that comes out twice a year. This time around, Cray's Jaguar has tried to catch IBM's Roadrunner and has come up with feathers in its mouth. Maybe Cray should have nicknamed it Wile E. Coyote?

Both machines are rated above 1 petaflops of number-crunching performance, and a whole bunch of other supers on the list are moving into the quadrillion ops arena. IBM's Roadrunner machine, which is installed at the Los Alamos National Laboratory, one of the handful of labs operated by the U.S. Department of Energy, was upgraded over the summer, thereby denying Cray's Jaguar bragging rights. But not by much.

The Roadrunner machine, which is a hybrid Opteron-Cell box custom blade box made by IBM, was upgraded a bit to push its performance to 1.105 sustained petaflops, up from 1.026 petaflops on the June 2008 list. Roadrunner was the first machine to crack the petaflops barrier. Beep, beep!

But Cray's Jaguar XT5 Opteron-based massively parallel super, installed at another DOE site at Oak Ridge National Laboratory, got more upgrades this cycle and was able to boost sustained performance from 205 teraflops using XT4 frames and 2.1 GHz quad-core Opterons to a much larger XT5 machine rated at 1.059 sustained petaflops.

As we go to press, the feeds and speeds of these two boxes in the Top 500 list, as well as the other 498 machines, are not yet available. Starting with the June 2008 list, machines were also rated for their power consumption, making it possible to rank the supers based on how many flops per watt they deliver. Another interesting game to play with the Top 500 list is to compare sustained performance on the Linpack test to peak performance, giving a sense of the efficiency and true cost of a particular super and its architecture.

The Top 500 list is put together twice a year to provide the feeds and speeds of the fastest 500 supercomputers in the world. Erich Strohmaier and Horst Simon, computer scientists at Lawrence Berkeley National Laboratory, Jack Dongarra of the University of Tennessee, and Hans Meuer of the University of Manheim make the list, which is based on the Linpack Fortran benchmark test created by Dongarra and colleagues Jim Bunch, Cleve Moler, and Pete Stewart back in the 1970s to gauge the relative performance of computers of all stripes and sizes on numerical calculations. The official Top 500 list came out in 1993, and this November 2008 compilation is the 32nd edition of the list.

Cray, which has been struggling financially and adversely impacted by the delay in the "Budapest" quad-core Opterons from Advanced Micro Devices that are used in the XT line of supers, is obviously very happy to be at the top of the list and in contention for the title. Cray may bear the name of the venerable maker of supercomputers from the 1970s, but it is an amalgam of supercomputer makers and architectures that are being converged to make Cray a credible alternative to IBM for custom supers here in the States. (The U.S. government likes to have at least two indigenous suppliers of high-end gear, more if possible, and has funded a substantial amount of the research behind super designs from IBM, Cray, and Silicon Graphics).

SGI has also in recent years moved away from its Itanium-based, global memory Altix 4700 supercomputers (kickers to its old NUMA-MIPS machines) and towards its Altix ICE blade designs, which are based on x64 processors. SGI wants to be in the game of supplying big iron to government labs and agencies. And NASA's Ames Research Center is SGI's sugar daddy, as it has been for a long time, and in the November 2008 ranking, the "Pleides" Altix ICE super has just squeaked by the former leader on the list, a BlueGene/L Linux-Power machine, to take the fourth spot in the list.

The SGI Pleides machine was ranked at 487 teraflops of sustained performance, pushing the BlueGene/L box at Lawrence Livermore National Laboratory, rated at 478.2 teraflops, down to the fourth slot in the list. Number five on the list is also an IBM box - also installed at a U.S. government lab - the BlueGene/P kicker to BlueGene/L, which is running at the DOE's Argonne National Laboratory and which is rated at 450.3 teraflops after some upgrading during the summer months.